(a) Field of the Invention
This invention relates to a method for artificially curing green tobacco with sulfur dioxide.
(b) State of the Art
Green leaf curing and/or aging by suspending the leaves in darkness or otherwise disposing the leaves while controlling temperature and relative humidity of circulating air currents is disclosed in U.S. Pat. Nos. 1,113,902, 1,543,245, 1,545,811, 1,568,316, 2,343,345 and 3,086,553. Forced air flow through bundles of green leaves has also been suggested as a means to cure green tobacco in U.S. Pat. No. 3,225,456. Such conventional methods of curing tobacco, characteristically require several days and may entail substantial expenditures for fuel. Further such curing processes tend to be labor intensive. In contrast to the majority of prior art curing methods, the present invention provides a rapid and less labor and energy intensive means for eliminating the green color and green odor and taste of tobacco employing sulfur dioxide.
U.S. Pat. No. 1,847,162 describes a process wherein sulfur dioxide is employed alone or preferably in combination with benzoyl peroxide as a bleaching or brightening agent for tobacco hands. According to this process, tobacco hands are placed in an air or gas tight enclosure, moistened to sensitize the tobacco to the bleaching agent; and contacted with the bleaching agent in gaseous form for 20 minutes to four hours. The enclosure is then aerated to expel the gas and dry the tobacco. The tobacco's combustion properties are then restored by treatment with an appropriate agent such as potassium nitrate vapors. Thereafter the tobacco is again aerated to render it fresh. The bleached tobacco is particularly useful as cigar wrapper. In contrast to this prior art tobacco treatment process, the present invention employs sulfur dioxide to cure green tobacco.